Abstract

We present an experimental study of near-field optical interactions between an optical probe and sample objects with different dielectric properties. The interaction strongly affects the radiation emitted at angles beyond the critical angle of total internal reflection in the substrate (the forbidden light regime). Such an effect has been predicted theoretically. Our experimental data show that if a conducting object is close to the optical probe, p-polarized optical fields are deflected away from the object. On the other hand, s-polarized fields are deflected toward dielectric objects. The experimental results show good qualitative agreement with numerical simulations. The described effects have a strong influence on image formation in scanning near-field optical microscopy and thus have to be taken into account for image analysis.

© 1999 Optical Society of America

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  1. For a review of research in the field, see Proceedings of the IVth International Conference on Near-Field Optics and Related Techniques, P. Kruit, S. M. Lindsay, eds., Ultramicroscopy71, 1–398 (1998).
  2. A. Dereux, D. W. Pohl, “The 90° prism edge as a model SNOM probe: near-field, photon tunneling, and far-field properties,” in Near Field Optics, D. W. Pohl, D. Courjon, eds. (Kluwer Academic, Dordrecht, The Netherlands, 1993), Vol. 242, pp. 189–198.
  3. H. Heinzelmann, B. Hecht, D. W. Pohl, L. Novotny, “Forbidden light scanning near-field optical microscopy,” J. Microsc. 177, 115–118 (1994).
    [CrossRef]
  4. B. Hecht, H. Heinzelmann, D. W. Pohl, “Combined aperture SNOM/PSTM: best of both worlds?” in Proceedings of the 2nd International Conference on Near-Field Optics, P. Kruit, ed., Ultramicroscopy57, 228–234 (1995).
    [CrossRef]
  5. J. Koglin, U. C. Fischer, K. D. Brzoska, W. Göhde, H. Fuchs, “The tetrahedral tip as a probe for scanning near-field optical and for scanning tunneling microscopy,” in Photons and Local Probes, O. Marti, R. Möller, eds. (Kluwer Academic, Dordrecht, The Netherlands, 1995), Vol. 300, pp. 79–92.
  6. B. Hecht, H. Heinzelmann, D. W. Pohl, L. Novotny, “ ‘Tunnel’ near-field optical microscopy: TNOM-2,” in Photons and Local Probes, O. Marti, R. Möller, eds. (Kluwer Academic, Dordrecht, The Netherlands, 1995), Vol. 300, pp. 93–107.
  7. B. Hecht, H. Bielefeldt, L. Novotny, Y. Inouye, D. W. Pohl, “Local excitation, scattering, and interference of surface plasmons,” Phys. Rev. Lett. 77, 1889–1892 (1996).
    [CrossRef] [PubMed]
  8. Ch. Hafner, The Generalized Multiple Multipole Technique for Computational Electromagnetics (Artech House, Boston, 1990).
  9. L. Novotny, D. W. Pohl, P. Regli, “Light propagation through nanometer-sized structures: the two-dimensional-aperture scanning near-field optical microscope,” J. Opt. Soc. Am. A 11, 1768–1779 (1994).
    [CrossRef]
  10. K. Karrai, R. D. Grober, “Piezoelectric tip–sample distance control for near field optical microscopes,” Appl. Phys. Lett. 66, 1842–1844 (1995).
    [CrossRef]
  11. L. Novotny, D. W. Pohl, “Light propagation in scanning near-field optical microscopy,” in Photons and Local Probes, O. Marti, R. Möller, eds. (Kluwer Academic, Dordrecht, The Netherlands, 1995), Vol. 300, pp. 21–33.
  12. D. Van Labeke, D. Barchiesi, F. Baida, “Optical characterization of nanosources used in scanning near-field optical microscopy,” J. Opt. Soc. Am. A 12, 695–703 (1995).
    [CrossRef]
  13. D. Van Labeke, F. Baida, D. Barchiesi, D. Courjon, “A theoretical model for the inverse scanning tunneling optical microscope (ISTOM),” Opt. Commun. 114, 470–480 (1995).
    [CrossRef]
  14. D. Barchiesi, D. Van Labeke, “The inverse scanning tunneling near-field microscope (ISTOM) or tunnel scanning near-field optical microscope (TSNOM): 3D simulations and application to nano-sources,” in Proceedings of the IIIrd International Conference on Near-Field Optics and Related Techniques, P. Kruit, S. M. Lindsay, eds., Ultramicroscopy61, 17–20 (1995).
    [CrossRef]
  15. D. A. Higgins, D. A. Vanden Bout, J. Kerimon, P. F. Barbara, “Polarization-modulation near-field optical microscopy of mesostructured materials,” J. Phys. Chem. 100, 13794–13803 (1996).
    [CrossRef]
  16. Th. Lacoste, Th. Huser, R. Prioli, H. Heinzelmann, “Contrast enhancement using polarization-modulation scanning near-field optical microscopy (PM-SNOM),” in Proceedings of the IVth International Conference on Near-Field Optics and Related Techniques, P. Kruit, S. M. Lindsay, eds., Ultramicroscopy71, 333–340 (1998).
    [CrossRef]
  17. Th. Huser, “Polarization contrast in allowed and forbidden light scanning near-field optical microscopy,” Ph.D. dissertation (University of Basel, Basel, Switzerland, 1998).

1996 (2)

B. Hecht, H. Bielefeldt, L. Novotny, Y. Inouye, D. W. Pohl, “Local excitation, scattering, and interference of surface plasmons,” Phys. Rev. Lett. 77, 1889–1892 (1996).
[CrossRef] [PubMed]

D. A. Higgins, D. A. Vanden Bout, J. Kerimon, P. F. Barbara, “Polarization-modulation near-field optical microscopy of mesostructured materials,” J. Phys. Chem. 100, 13794–13803 (1996).
[CrossRef]

1995 (3)

K. Karrai, R. D. Grober, “Piezoelectric tip–sample distance control for near field optical microscopes,” Appl. Phys. Lett. 66, 1842–1844 (1995).
[CrossRef]

D. Van Labeke, D. Barchiesi, F. Baida, “Optical characterization of nanosources used in scanning near-field optical microscopy,” J. Opt. Soc. Am. A 12, 695–703 (1995).
[CrossRef]

D. Van Labeke, F. Baida, D. Barchiesi, D. Courjon, “A theoretical model for the inverse scanning tunneling optical microscope (ISTOM),” Opt. Commun. 114, 470–480 (1995).
[CrossRef]

1994 (2)

Baida, F.

D. Van Labeke, F. Baida, D. Barchiesi, D. Courjon, “A theoretical model for the inverse scanning tunneling optical microscope (ISTOM),” Opt. Commun. 114, 470–480 (1995).
[CrossRef]

D. Van Labeke, D. Barchiesi, F. Baida, “Optical characterization of nanosources used in scanning near-field optical microscopy,” J. Opt. Soc. Am. A 12, 695–703 (1995).
[CrossRef]

Barbara, P. F.

D. A. Higgins, D. A. Vanden Bout, J. Kerimon, P. F. Barbara, “Polarization-modulation near-field optical microscopy of mesostructured materials,” J. Phys. Chem. 100, 13794–13803 (1996).
[CrossRef]

Barchiesi, D.

D. Van Labeke, F. Baida, D. Barchiesi, D. Courjon, “A theoretical model for the inverse scanning tunneling optical microscope (ISTOM),” Opt. Commun. 114, 470–480 (1995).
[CrossRef]

D. Van Labeke, D. Barchiesi, F. Baida, “Optical characterization of nanosources used in scanning near-field optical microscopy,” J. Opt. Soc. Am. A 12, 695–703 (1995).
[CrossRef]

D. Barchiesi, D. Van Labeke, “The inverse scanning tunneling near-field microscope (ISTOM) or tunnel scanning near-field optical microscope (TSNOM): 3D simulations and application to nano-sources,” in Proceedings of the IIIrd International Conference on Near-Field Optics and Related Techniques, P. Kruit, S. M. Lindsay, eds., Ultramicroscopy61, 17–20 (1995).
[CrossRef]

Bielefeldt, H.

B. Hecht, H. Bielefeldt, L. Novotny, Y. Inouye, D. W. Pohl, “Local excitation, scattering, and interference of surface plasmons,” Phys. Rev. Lett. 77, 1889–1892 (1996).
[CrossRef] [PubMed]

Brzoska, K. D.

J. Koglin, U. C. Fischer, K. D. Brzoska, W. Göhde, H. Fuchs, “The tetrahedral tip as a probe for scanning near-field optical and for scanning tunneling microscopy,” in Photons and Local Probes, O. Marti, R. Möller, eds. (Kluwer Academic, Dordrecht, The Netherlands, 1995), Vol. 300, pp. 79–92.

Courjon, D.

D. Van Labeke, F. Baida, D. Barchiesi, D. Courjon, “A theoretical model for the inverse scanning tunneling optical microscope (ISTOM),” Opt. Commun. 114, 470–480 (1995).
[CrossRef]

Dereux, A.

A. Dereux, D. W. Pohl, “The 90° prism edge as a model SNOM probe: near-field, photon tunneling, and far-field properties,” in Near Field Optics, D. W. Pohl, D. Courjon, eds. (Kluwer Academic, Dordrecht, The Netherlands, 1993), Vol. 242, pp. 189–198.

Fischer, U. C.

J. Koglin, U. C. Fischer, K. D. Brzoska, W. Göhde, H. Fuchs, “The tetrahedral tip as a probe for scanning near-field optical and for scanning tunneling microscopy,” in Photons and Local Probes, O. Marti, R. Möller, eds. (Kluwer Academic, Dordrecht, The Netherlands, 1995), Vol. 300, pp. 79–92.

Fuchs, H.

J. Koglin, U. C. Fischer, K. D. Brzoska, W. Göhde, H. Fuchs, “The tetrahedral tip as a probe for scanning near-field optical and for scanning tunneling microscopy,” in Photons and Local Probes, O. Marti, R. Möller, eds. (Kluwer Academic, Dordrecht, The Netherlands, 1995), Vol. 300, pp. 79–92.

Göhde, W.

J. Koglin, U. C. Fischer, K. D. Brzoska, W. Göhde, H. Fuchs, “The tetrahedral tip as a probe for scanning near-field optical and for scanning tunneling microscopy,” in Photons and Local Probes, O. Marti, R. Möller, eds. (Kluwer Academic, Dordrecht, The Netherlands, 1995), Vol. 300, pp. 79–92.

Grober, R. D.

K. Karrai, R. D. Grober, “Piezoelectric tip–sample distance control for near field optical microscopes,” Appl. Phys. Lett. 66, 1842–1844 (1995).
[CrossRef]

Hafner, Ch.

Ch. Hafner, The Generalized Multiple Multipole Technique for Computational Electromagnetics (Artech House, Boston, 1990).

Hecht, B.

B. Hecht, H. Bielefeldt, L. Novotny, Y. Inouye, D. W. Pohl, “Local excitation, scattering, and interference of surface plasmons,” Phys. Rev. Lett. 77, 1889–1892 (1996).
[CrossRef] [PubMed]

H. Heinzelmann, B. Hecht, D. W. Pohl, L. Novotny, “Forbidden light scanning near-field optical microscopy,” J. Microsc. 177, 115–118 (1994).
[CrossRef]

B. Hecht, H. Heinzelmann, D. W. Pohl, “Combined aperture SNOM/PSTM: best of both worlds?” in Proceedings of the 2nd International Conference on Near-Field Optics, P. Kruit, ed., Ultramicroscopy57, 228–234 (1995).
[CrossRef]

B. Hecht, H. Heinzelmann, D. W. Pohl, L. Novotny, “ ‘Tunnel’ near-field optical microscopy: TNOM-2,” in Photons and Local Probes, O. Marti, R. Möller, eds. (Kluwer Academic, Dordrecht, The Netherlands, 1995), Vol. 300, pp. 93–107.

Heinzelmann, H.

H. Heinzelmann, B. Hecht, D. W. Pohl, L. Novotny, “Forbidden light scanning near-field optical microscopy,” J. Microsc. 177, 115–118 (1994).
[CrossRef]

B. Hecht, H. Heinzelmann, D. W. Pohl, “Combined aperture SNOM/PSTM: best of both worlds?” in Proceedings of the 2nd International Conference on Near-Field Optics, P. Kruit, ed., Ultramicroscopy57, 228–234 (1995).
[CrossRef]

B. Hecht, H. Heinzelmann, D. W. Pohl, L. Novotny, “ ‘Tunnel’ near-field optical microscopy: TNOM-2,” in Photons and Local Probes, O. Marti, R. Möller, eds. (Kluwer Academic, Dordrecht, The Netherlands, 1995), Vol. 300, pp. 93–107.

Th. Lacoste, Th. Huser, R. Prioli, H. Heinzelmann, “Contrast enhancement using polarization-modulation scanning near-field optical microscopy (PM-SNOM),” in Proceedings of the IVth International Conference on Near-Field Optics and Related Techniques, P. Kruit, S. M. Lindsay, eds., Ultramicroscopy71, 333–340 (1998).
[CrossRef]

Higgins, D. A.

D. A. Higgins, D. A. Vanden Bout, J. Kerimon, P. F. Barbara, “Polarization-modulation near-field optical microscopy of mesostructured materials,” J. Phys. Chem. 100, 13794–13803 (1996).
[CrossRef]

Huser, Th.

Th. Huser, “Polarization contrast in allowed and forbidden light scanning near-field optical microscopy,” Ph.D. dissertation (University of Basel, Basel, Switzerland, 1998).

Th. Lacoste, Th. Huser, R. Prioli, H. Heinzelmann, “Contrast enhancement using polarization-modulation scanning near-field optical microscopy (PM-SNOM),” in Proceedings of the IVth International Conference on Near-Field Optics and Related Techniques, P. Kruit, S. M. Lindsay, eds., Ultramicroscopy71, 333–340 (1998).
[CrossRef]

Inouye, Y.

B. Hecht, H. Bielefeldt, L. Novotny, Y. Inouye, D. W. Pohl, “Local excitation, scattering, and interference of surface plasmons,” Phys. Rev. Lett. 77, 1889–1892 (1996).
[CrossRef] [PubMed]

Karrai, K.

K. Karrai, R. D. Grober, “Piezoelectric tip–sample distance control for near field optical microscopes,” Appl. Phys. Lett. 66, 1842–1844 (1995).
[CrossRef]

Kerimon, J.

D. A. Higgins, D. A. Vanden Bout, J. Kerimon, P. F. Barbara, “Polarization-modulation near-field optical microscopy of mesostructured materials,” J. Phys. Chem. 100, 13794–13803 (1996).
[CrossRef]

Koglin, J.

J. Koglin, U. C. Fischer, K. D. Brzoska, W. Göhde, H. Fuchs, “The tetrahedral tip as a probe for scanning near-field optical and for scanning tunneling microscopy,” in Photons and Local Probes, O. Marti, R. Möller, eds. (Kluwer Academic, Dordrecht, The Netherlands, 1995), Vol. 300, pp. 79–92.

Lacoste, Th.

Th. Lacoste, Th. Huser, R. Prioli, H. Heinzelmann, “Contrast enhancement using polarization-modulation scanning near-field optical microscopy (PM-SNOM),” in Proceedings of the IVth International Conference on Near-Field Optics and Related Techniques, P. Kruit, S. M. Lindsay, eds., Ultramicroscopy71, 333–340 (1998).
[CrossRef]

Novotny, L.

B. Hecht, H. Bielefeldt, L. Novotny, Y. Inouye, D. W. Pohl, “Local excitation, scattering, and interference of surface plasmons,” Phys. Rev. Lett. 77, 1889–1892 (1996).
[CrossRef] [PubMed]

H. Heinzelmann, B. Hecht, D. W. Pohl, L. Novotny, “Forbidden light scanning near-field optical microscopy,” J. Microsc. 177, 115–118 (1994).
[CrossRef]

L. Novotny, D. W. Pohl, P. Regli, “Light propagation through nanometer-sized structures: the two-dimensional-aperture scanning near-field optical microscope,” J. Opt. Soc. Am. A 11, 1768–1779 (1994).
[CrossRef]

L. Novotny, D. W. Pohl, “Light propagation in scanning near-field optical microscopy,” in Photons and Local Probes, O. Marti, R. Möller, eds. (Kluwer Academic, Dordrecht, The Netherlands, 1995), Vol. 300, pp. 21–33.

B. Hecht, H. Heinzelmann, D. W. Pohl, L. Novotny, “ ‘Tunnel’ near-field optical microscopy: TNOM-2,” in Photons and Local Probes, O. Marti, R. Möller, eds. (Kluwer Academic, Dordrecht, The Netherlands, 1995), Vol. 300, pp. 93–107.

Pohl, D. W.

B. Hecht, H. Bielefeldt, L. Novotny, Y. Inouye, D. W. Pohl, “Local excitation, scattering, and interference of surface plasmons,” Phys. Rev. Lett. 77, 1889–1892 (1996).
[CrossRef] [PubMed]

H. Heinzelmann, B. Hecht, D. W. Pohl, L. Novotny, “Forbidden light scanning near-field optical microscopy,” J. Microsc. 177, 115–118 (1994).
[CrossRef]

L. Novotny, D. W. Pohl, P. Regli, “Light propagation through nanometer-sized structures: the two-dimensional-aperture scanning near-field optical microscope,” J. Opt. Soc. Am. A 11, 1768–1779 (1994).
[CrossRef]

L. Novotny, D. W. Pohl, “Light propagation in scanning near-field optical microscopy,” in Photons and Local Probes, O. Marti, R. Möller, eds. (Kluwer Academic, Dordrecht, The Netherlands, 1995), Vol. 300, pp. 21–33.

A. Dereux, D. W. Pohl, “The 90° prism edge as a model SNOM probe: near-field, photon tunneling, and far-field properties,” in Near Field Optics, D. W. Pohl, D. Courjon, eds. (Kluwer Academic, Dordrecht, The Netherlands, 1993), Vol. 242, pp. 189–198.

B. Hecht, H. Heinzelmann, D. W. Pohl, “Combined aperture SNOM/PSTM: best of both worlds?” in Proceedings of the 2nd International Conference on Near-Field Optics, P. Kruit, ed., Ultramicroscopy57, 228–234 (1995).
[CrossRef]

B. Hecht, H. Heinzelmann, D. W. Pohl, L. Novotny, “ ‘Tunnel’ near-field optical microscopy: TNOM-2,” in Photons and Local Probes, O. Marti, R. Möller, eds. (Kluwer Academic, Dordrecht, The Netherlands, 1995), Vol. 300, pp. 93–107.

Prioli, R.

Th. Lacoste, Th. Huser, R. Prioli, H. Heinzelmann, “Contrast enhancement using polarization-modulation scanning near-field optical microscopy (PM-SNOM),” in Proceedings of the IVth International Conference on Near-Field Optics and Related Techniques, P. Kruit, S. M. Lindsay, eds., Ultramicroscopy71, 333–340 (1998).
[CrossRef]

Regli, P.

Van Labeke, D.

D. Van Labeke, D. Barchiesi, F. Baida, “Optical characterization of nanosources used in scanning near-field optical microscopy,” J. Opt. Soc. Am. A 12, 695–703 (1995).
[CrossRef]

D. Van Labeke, F. Baida, D. Barchiesi, D. Courjon, “A theoretical model for the inverse scanning tunneling optical microscope (ISTOM),” Opt. Commun. 114, 470–480 (1995).
[CrossRef]

D. Barchiesi, D. Van Labeke, “The inverse scanning tunneling near-field microscope (ISTOM) or tunnel scanning near-field optical microscope (TSNOM): 3D simulations and application to nano-sources,” in Proceedings of the IIIrd International Conference on Near-Field Optics and Related Techniques, P. Kruit, S. M. Lindsay, eds., Ultramicroscopy61, 17–20 (1995).
[CrossRef]

Vanden Bout, D. A.

D. A. Higgins, D. A. Vanden Bout, J. Kerimon, P. F. Barbara, “Polarization-modulation near-field optical microscopy of mesostructured materials,” J. Phys. Chem. 100, 13794–13803 (1996).
[CrossRef]

Appl. Phys. Lett. (1)

K. Karrai, R. D. Grober, “Piezoelectric tip–sample distance control for near field optical microscopes,” Appl. Phys. Lett. 66, 1842–1844 (1995).
[CrossRef]

J. Microsc. (1)

H. Heinzelmann, B. Hecht, D. W. Pohl, L. Novotny, “Forbidden light scanning near-field optical microscopy,” J. Microsc. 177, 115–118 (1994).
[CrossRef]

J. Opt. Soc. Am. A (2)

J. Phys. Chem. (1)

D. A. Higgins, D. A. Vanden Bout, J. Kerimon, P. F. Barbara, “Polarization-modulation near-field optical microscopy of mesostructured materials,” J. Phys. Chem. 100, 13794–13803 (1996).
[CrossRef]

Opt. Commun. (1)

D. Van Labeke, F. Baida, D. Barchiesi, D. Courjon, “A theoretical model for the inverse scanning tunneling optical microscope (ISTOM),” Opt. Commun. 114, 470–480 (1995).
[CrossRef]

Phys. Rev. Lett. (1)

B. Hecht, H. Bielefeldt, L. Novotny, Y. Inouye, D. W. Pohl, “Local excitation, scattering, and interference of surface plasmons,” Phys. Rev. Lett. 77, 1889–1892 (1996).
[CrossRef] [PubMed]

Other (10)

Ch. Hafner, The Generalized Multiple Multipole Technique for Computational Electromagnetics (Artech House, Boston, 1990).

For a review of research in the field, see Proceedings of the IVth International Conference on Near-Field Optics and Related Techniques, P. Kruit, S. M. Lindsay, eds., Ultramicroscopy71, 1–398 (1998).

A. Dereux, D. W. Pohl, “The 90° prism edge as a model SNOM probe: near-field, photon tunneling, and far-field properties,” in Near Field Optics, D. W. Pohl, D. Courjon, eds. (Kluwer Academic, Dordrecht, The Netherlands, 1993), Vol. 242, pp. 189–198.

B. Hecht, H. Heinzelmann, D. W. Pohl, “Combined aperture SNOM/PSTM: best of both worlds?” in Proceedings of the 2nd International Conference on Near-Field Optics, P. Kruit, ed., Ultramicroscopy57, 228–234 (1995).
[CrossRef]

J. Koglin, U. C. Fischer, K. D. Brzoska, W. Göhde, H. Fuchs, “The tetrahedral tip as a probe for scanning near-field optical and for scanning tunneling microscopy,” in Photons and Local Probes, O. Marti, R. Möller, eds. (Kluwer Academic, Dordrecht, The Netherlands, 1995), Vol. 300, pp. 79–92.

B. Hecht, H. Heinzelmann, D. W. Pohl, L. Novotny, “ ‘Tunnel’ near-field optical microscopy: TNOM-2,” in Photons and Local Probes, O. Marti, R. Möller, eds. (Kluwer Academic, Dordrecht, The Netherlands, 1995), Vol. 300, pp. 93–107.

D. Barchiesi, D. Van Labeke, “The inverse scanning tunneling near-field microscope (ISTOM) or tunnel scanning near-field optical microscope (TSNOM): 3D simulations and application to nano-sources,” in Proceedings of the IIIrd International Conference on Near-Field Optics and Related Techniques, P. Kruit, S. M. Lindsay, eds., Ultramicroscopy61, 17–20 (1995).
[CrossRef]

L. Novotny, D. W. Pohl, “Light propagation in scanning near-field optical microscopy,” in Photons and Local Probes, O. Marti, R. Möller, eds. (Kluwer Academic, Dordrecht, The Netherlands, 1995), Vol. 300, pp. 21–33.

Th. Lacoste, Th. Huser, R. Prioli, H. Heinzelmann, “Contrast enhancement using polarization-modulation scanning near-field optical microscopy (PM-SNOM),” in Proceedings of the IVth International Conference on Near-Field Optics and Related Techniques, P. Kruit, S. M. Lindsay, eds., Ultramicroscopy71, 333–340 (1998).
[CrossRef]

Th. Huser, “Polarization contrast in allowed and forbidden light scanning near-field optical microscopy,” Ph.D. dissertation (University of Basel, Basel, Switzerland, 1998).

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Figures (7)

Fig. 1
Fig. 1

(a) Setup of our forbidden light near-field optical microscope. The difference with previous setups6 consists in the additional detection window. (b) Measured intensity-to-distance curves for allowed and forbidden light. The intensity values are normalized data.

Fig. 2
Fig. 2

Sequence of field plots for a probe–sample system, obtained by MMP calculations. The probe consists of a glass wedge coated with aluminum. S-polarized light with a wavelength of 488 nm is incident on an aluminum particle lying 0, 20, and 50 nm under the aperture. The observed penetration of the radiation into the metal is due to the finite conductivity of aluminum. An off-center position of the particle leads to a deflection of the field distribution described by the term near-field optical diffraction.

Fig. 3
Fig. 3

(a) A latex projection pattern was prepared by depositing 15 nm of aluminum on latex spheres with a diameter of 450 nm. After the spheres are removed, a pattern of aluminum islands is left on the substrate. (b) Allowed light image of the pattern as measured in constant-height mode. For clarification, the pattern is overlaid on the right. (c) The topographical image is featureless, indicating constant-height imaging, except for a few scan lines at the beginning of the scan. Image size is 2.25×2.25 µm.

Fig. 4
Fig. 4

Forbidden light images with a scan size of 2.25 µm×2.25 µm for different azimuthal angles φ of the detection window. For clarifying illustration, the insets in the upper left corner of each part represent the configuration of the experiment: (a) φ=0°, (b) φ=180°, (c) φ=90°, (d) φ=270°. The insets marked in (a) and (b) are further used in Fig. 5.

Fig. 5
Fig. 5

Enlarged representation of the insets in Fig. 4 for two perpendicular settings of the detection window. (a) φ=0°. (b) φ=180°. (c) Line sections through experimental data [I and II as labeled in (a) and (b)]. The approximate position of the aluminum island is illustrated by the black bar. (d) Computed line sections. Only the left (I) or the right (II) lobe of the far-field intensity distribution was calculated, displaying a field enhancement near the particle. The particle is illustrated by the black dot.

Fig. 6
Fig. 6

Measured light intensity across a 90-nm-high dielectric step. Light intensity is shown in arbitrary units, and the scales of forbidden light (FL) and allowed light (AL) are different, since the observed effects are investigated only qualitatively. The numbers behind the FL labels indicate the setting of the detection window. (a) Polarization perpendicular to the step (p polarization), (b) polarization parallel to the step (s polarization).

Fig. 7
Fig. 7

Simulated light intensity across a 70-nm step for (a) p polarization and (b) s polarization.

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